| ABSTRACT: |
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Naturally occurring components of the human food supply have recently
received attention as possible agents for cancer chemoprevention. The
plant phenol ellagic acid has been reported to be an effective inhibitor
of carcinogen metabolism and certain chemically induced tumors. Therefore,
we evaluated the efficacy of ellagic acid in inhibiting DMBA metabolism,
DNA binding, and the initiation of DMBA-induced carcinogenesis in rat
mammary tissue. Mammary epithelial cell aggregates were isolated from rats
fed control and ellagic acid (0.4 and 0.8%) diets. When incubated with
DMBA, aggregates from ellagic acid-fed rats exhibited a significant but
modest inhibition of DMBA metabolism and DNA binding. An inhibition of
DMBA-DNA binding and DMBA metabolism in secondary cultures of mammary
epithelial cells also was detected only when ellagic acid was added at 150
molar excess compared to DMBA. The feeding of ellagic acid (0.8%) to rats
for 28 days prior to the administration of DMBA resulted in a 21%
reduction in mammary tumor incidence at 21 wk, which was, however, not
statistically significant. Together, these results indicate that, in
contrast to its effects with other carcinogens in other tissues, ellagic
acid is not a potent inhibitor of DMBA metabolism, DNA binding, and
carcinogenicity with rat mammary tissue. (9 Refs) |